Circuit breaker



June 11, 1968 MQPAGANELLI CIRCUIT BREAKER '4 Sheets-Sheet 1 Filed Jan. 21, 1965 INVENTOR June 11,1968 M. PAGANELLI CIRCUIT BREAKER 4 Sheets-Sheet 2 Filed Jan. 21, 1965 INVENTOR ATTORNEY June 11, 1968 M. PAGANELLI CIRCUIT BREAKER Filed Jan. 21. 1965 4Sheets-Sheet I5 EM. r

INVENTOR 1 4G170 [Q4 BY 9008/ l K (AZ-:1 3 gnaw ATTORNEY June 11, 1968 M. PAGANELLI CIRCUIT BREAKER 4 Sheets-Sheet 4 Filed Jan. 21, 1965 I NVENTO R fi/Gf/ O BY 561/ 6 L fiu/Midf 5 $2 02.

ATTORNEY United States Patent 3,388,358 CIRCUIT BREAKER Mario Paganclli, Varese, Italy, assignor to Bassani, S.p.A., Milan, Italy Filed Jan. 21, 1965, Ser. No. 426,763 Claims priority, application Italy, Apr. 11, 1964,

12 Claims. (Cl. 335-191) ABSTRACT OF THE DISCLOSURE A circuit breaker in which at least one movable contact engaging a corresponding stationary contact is carried on one end of a spring-loaded arm pivotally supported on a lever system cooperating with current controlled means actuated during an overload, in which the elements of the circuit breaker are arranged and constructed to keep the contacts, in absence of an overload, in engagement with each other and to pivot, during an overload, the arm first in one direction about the point of engagement between the contacts until the other end of the arm engages a stop, and to turn then the arm in the opposite direction about the point of engagement of the other end of the arm with the stop to rapidly open the circuit breaker.

BACKGROUND OF THE INVENTION The present invention relates to circuit breakers, and more specifically to a circuit breaker of small size adapted to be mounted in a wall bracket with other electrical components such as outlet sockets, switches, or the like.

It is an object of the present invention to provide for a small size circuit breaker which automatically opens when an overload occurs in the circuit to which the circuit breaker is connected.

It is a further object of the present invention to provide for a small circuit breaker which will function reliably and which will stand up under extended use.

SUMMARY OF THE INVENTION With these objects in view, the circuit breaker according to the present invention mainly comprises a support, at least one stationary contact mounted on the support, at least one arm carrying in the region at one end thereof a movable contact engaging the stationary contact, a first lever pivotally connected in the region of one end thereof to the aforementioned arm for pivotal movement about a first pivot axis located intermediate the ends of the arm, a second lever pivotally connected in the region of one end thereof to the first lever for pivotal movement about the second pivot axis located intermediate the ends of the first lever, an operating member movably mounted on the support to which the second lever is pivotally connected for pivotal movement about a third pivot axis spaced from the second pivot axis, the aforementioned pivot axes are located in a common plane, a stop member fixed to the support and located spaced from the other end of the arm and on the side of the latter facing away from the stationary contact, biasing means engaging with the arm intermediate the other end and the first pivot axis and biasing the one end of the arm which carries the movable contact toward the stationary contact, and current controlled means on the support means and cooperating wtih the first lever to turn the latter during an overload about the first pivot axis in a direction in which the second pivot axis is moved out of the aforementioned common plane so that the arm will pivot under the influence of the biasing means first in one direction about the point of engagement between the contacts until the other end of the arm engages the stop means, whereupon the arm will pivot in the opposite direction about the point of contact of the other end thereof with the stop means to rapidly open the circuit breaker.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective outside view of the circuit breaker according to the present invention;

FIG. 2 is a perspective view illustrating the circuit breaker mounted in a wall bracket;

FIG. 3 is a perspective view similar to FIG. 1, with part of the housing of the circuit breaker broken away to show the elements of the circuit breaker in the housing, and wherein the circuit breaker is shown in open position;

FIG. 4 is a perspective view similar to FIG. 3 with the housing completely omitted and showing the circuit breaker in closed position;

FIG. 5 is a schematic side view illustrating some of the elements of the circuit breaker in closed position of the latter;

FIG. 6 is a schematic side view similar to FIG. 5 showing the elements during the first part of the opening movement;

FIG. 7 is a schematic side view similar to FIG. 6 and showing thecircuit breaker in open position;

FIG. 8 is a perspective view similar to FIG. 4 and showing the circuit breaker in the open position; and

FIG. 9 is a wiring diagram of the circuit breaker.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and more specifically to FIG. 1 of the same, it will be seen that the circuit breaker according to the present invention comprises a support in the form of a housing 8 of insulating material and preferably substantially in the form of a square prism which is closed at its upper open end by a cover 9 which has in the front and the rear downwardly extending clips 11 engaging with projections 10 on the front and the rear wall of the housing 8. The cover 9 is formed with an opening through which an operating member of the circuit breaker in form of a rocker 14 which will be described later on in detail projects outwardly of the housing.

As shown in FIG. 2, the cover 9 serves to fasten the circuit breaker-to the supporting frame 15 provided to enable other electrical equipment, such as conventional switches, pushbuttons, or sockets, to be mounted flush with the plaster layer of a wall. Frame 15 is usually covered by means of a cover plate 12 provided with small apertures through which the control members of the various devices supported thereby project outwardly.

As shown in FIGS. 3, 4 and 8 the circuit breaker according to the present invention comprises further two fixed contact carriers 16 and 17 resting on and preferably connected in any convenient manner to the bottom walls 17' of the housing 8 and connected at the rear, or right ends thereof, as viewed in the aforementioned figures, to two terminals 18 and 19, whereas the other ends of the contact carriers 16 and 17 carry stationary contacts. An offset plate member 20 rests on the upper surface of the contact carrier 16 and partly covers the terminals 18 and 19.

The movable contacts, which in the closed position of the circuit breaker as shown in FIG. 4 engage the stationary contacts, are respectively supported on a pair of arms 21 and 22 of electrically conductive material mechanically and electrically connected to each other by a pair of transverse shafts or rods 23 and 26. A first lever 27 is pivotally connected in the region of its bottom end to the transverse rod 26 between the arms 21 and 22, and the lever 27 is in turn, intermediate its ends, pivotally connected by a pin 28 to the bottom end of a stirrup-shaped second lever 29 between the legs of which the lever 27 may pivot. The lever 29 is pivotally connected intermediate the ends thereof by means of a pin extending between two lugs 30 projecting downwardly from the rocker 14. A spring 31 is wound about opposite ends of the last-mentioned pivot pin and the ends of the springs 31 are fastened to the rocker 14, whereas the middle portion of the spring forms a bridge 32 resting on the lever 29. The rocker 14 is pivoted by means of lateral projections 46 in the side walls of the housing 8 and on the cover 9 as best shown in FIGS. 1 and 3. In the closed position of the circuit breaker the axes of all aforementioned described pivots are located in a common plane as best shown in FIG. 5. Biasing means, preferably in form of coil compression springs 24 and 25 abut with the bottom ends thereof against the plate 20, whereas the top ends of the springs 24 and 25 respectively engage the levers 21 and 22 at the bottom faces thereof intermediate the transverse rod 26 and the rear or right end of the arms, as viewed for instance in FIG. 4, to thus apply, in the position of the members of the circuit breaker as shown in FIG. 4, to the arms a moment in counterclockwise direction about the axis of the transverse shaft 26 so as to maintain the movable contacts in engagement with the stationary contacts.

The release lever 27 has two projections, a projection 33 about the pivot pin 28 and a projection 34 at the upper end thereof. The projection 33 is situated in front of the armature 35 of an electromagnetic trip relay 36, and projection 34 is located in front of a pusher 37 of a thermal trip 38.

When both levers 27 and 29 are disposed as shown in FIG. 4 so that the three aforementioned pivot axes are aligned in a common plane, the front ends of the arms 21 and 22 will be pushed downwardly thus maintaining the circuit breaker in the closed position. The shafts 23 and 26 are not connected to any fixed part of the circuit breaker, and the arms 21 and 22 and the shafts 23 and 26 together constitute a mobile frame subjected only to the action of the springs 24 and 25 and to that of the lever 27.

When the circuit breaker is in its closed position, both levers 27 and 29 are aligned, the movable contacts are pressed against the stationary contacts, and the springs 24 and 25 are compressed. When an overload or a shortcircuit occurs in the electrical circuit connected to the circuit breaker, lever 27 is moved, due to the action of pusher 37 or armature 35 to rotate in counterclockwise direction about the pivot axis of shaft 26, and in this way (FIG. 9) displaces the pin 28 out of the common plane in which the shaft 26 and the pin on rocker 14 are located. Due to this displacement and due to the position of the compressed springs 24 and 25, the arms 21 and 22 will thereby first pivot about the points of engagement of the movable contacts with the stationary contacts until the rear ends or right ends of the arms, as viewed in FIG. 6 will engage with the bottom face of a stop member 45 fixed to and projecting forwardly from the rear wall of the housing. Thereafter the springs 24 and 25 will urge the arms to move in clockwise direction to the position shown in FIG. 7, thereby opening the circuit breaker.

It will be noticed that this movement of the arms 21 and 22 imparts a very quick separation of the contacts, since during the first part of the opening movement, all elements capable of generating friction, as for example the pivots, are displaced, so that the remaining movement is practically frictionless.

Such a quick separation of the contacts limits the formation of electric arcs, thus ensuring a longer life of the contacts and improving the operation of the circuit breaker.

In the open position, the circuit breaker stays as illustrated in FIG. 8.

In order to bring the circuit breaker back to its closed position it is only necessary to pivot rocker 14. During the first movement of the rocker 14 to the position shown in broken lines in FIG. 8, the spring 31 will act to bring pins 28 and 26 into line with the pivot pin on the lugs 30. Return of the rocker 14 to its solid line position is effective to cause levers 27 and 29 to push the frame comprising arms 21 and 22 and shafts 23 and 26 downwardly which brings the movable contacts into engagement with the fixed contacts while the springs 24 and 25 are compressed and the circuit breaker will resume the position as shown in FIG. 4.

Opening of the circuit breaker can be manually performed by tilting the rocker about its fulcrum 46 to thereby displace the lugs 3t) and with it the levers 27 and 29. These levers, once displaced will continue to move due to the force exerted on them by shaft 26 due to springs 24 and 25, thus effecting the opening of the contacts.

As shown in FIG. 3, the fixed and movable contacts are disposed within respective enclosures 39 and 40, each of which is separated from the other by means of double walls between which an air gap 41 is left. The front walls of the aforementioned enclosures are provided with ventilating openings 42 and the upper part of the respective enclosure is formed with a larger aperture 43. In this manner, the enclosures provide exhaust passages for the hot gases generated by arcing at the contacts, thus favoring de-ionization of the air within the enclosures with consequent extinguishing of the arcs.

As illustrated in FIG. 9 the electric path through the circuit breaker is from the terminal 18 to the contact carrier 16, the stationary contact at one end thereof, the movable contact on the arm 21 and through the latter, through shafts 23 and 26 to the arm 22 through the movable contact at the end of this arm to the stationary contact on the contact carrier 17 t0 the terminal 44 at the other end of the contact carrier 17, through coil 36 of the trip relay, through the thermal relay 38, and from there to the other terminal contact 19.

It will be seen that this invention provides for a miniature circuit breaker of very simple construction, of small dimensions and which can be produced at low cost and which will be safe in operation.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other type of circuit breakers differin g from the types described above.

While the invention has been illustrated and described as embodied in a circuit breaker automatically opening under overload, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the pmsent invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

I claim:

1. A circuit breaker comprising, in combination, a support; at least one stationary contact mounted on said support; at least one arm carrying in the region at one end thereof a movable contact engaging said stationary contact; a first lever pivotally connected in the region of one end thereof to said arm for pivotal movement about a first pivot axis located intermediate the ends of said arm; a second lever pivotally connected in the region of one end thereof to said first lever for pivotal movement about a second pivot axis located intermediate the ends of said first lever; an operating member movably mounted on said support, said second lever being pivotally connected in spaced relation to said second pivot axis to said operating member for pivotal movement about a third pivot axis, said pivot axes being located in a com mon plane; a stop member fixed to said support and being located in spaced relation to the other end of said arm and on the side of the latter facing away from said stationary contact; biasing means engaging said arm intermediate said other end and said first pivot axis and biasing said one end of said arm toward said stationary contact; and current controlled means on said support cooperating with said first lever to turn the latter during an overload about said first pivot axis in a direction in which said second pivot axis is moved out of said common plane so that said arm will pivot under the influence of said biasing means first in one direction about the point of engagement between said contacts until said other end of said arm engages said stop means, whereupon said arm will pivot in the opposite direction about the point of contact of said other end thereof with said stop means to rapidly open said circuit breaker.

2. A circuit breaker as defined in claim 1, wherein said biasing means comprises spring means.

3. A circuit breaker as defined in claim 1, wherein said support is a housing of insulating material in which the elements of said circuit breaker are housed.

4. A circuit breaker as defined in claim 3, wherein said biasing means is a coil compression spring engaging with one end a wall of said housing and with the other end that side of said arm which faces away from said stop means.

5. A circuit breaker as defined in claim 1, wherein said current controlled means comprises an electromagnetic trip relay having a movable armature adapted to cooperate with said first lever to turn the latter about said first pivot axis.

6. A circuit breaker as defined in claim 5, wherein said current controlled means comprises further a thermal trip having a pusher adapted to cooperate with said first member to turn the latter about said first pivot axis.

7. A circuit breaker as defined in claim 6, wherein said first lever has a pair of projections located spaced from each other between said second pivot axis and the other end of said first lever, said armature and said pusher being arranged to cooperate respectively with said projections.

.8. A circuit breaker as defined in claim 1, wherein two stationary contacts are provided and two arms each carrying on one end thereof a movable contact engaging respectively one of said two stationary contacts, said arms being connected to each other for simultaneous movement about said first pivot axis.

9. A circuit breaker as defined in claim 8, wherein said arms are of electrically conductive material and are mechanically and electrically connected to each other, and including a terminal contact connected to each stationary contact.

10. A circuit breaker as defined in claim 9, wherein said support comprises a housing having a bottom wall and a front wall, said stationary contacts being mounted on said bottom wall, and said housing including a separating wall integral with said bottom and front walls and extending between the two stationary and said two movable contacts.

11. A circuit breaker as defined in claim 10, wherein said front wall of said housing is provided with ventilating openings.

12. A circuit breaker as defined in claim 10, wherein said operating member is in the form of a rocker member projecting in part beyond and being pivotably mounted on said housing spaced from said bottom wall, said rocker member having portions projecting toward said bottom wall to which said second lever is pivotably connected.

No references cited.

BERNARD A. GILHEANY, Primary Examiner. G. HARRIS, Examiner. 

